Stethoscope



May 16, 1939. s. slLKA 2,158,764

STETHOSCOPE Filed June 18, 1937 Patented May 16, 1939 UNITED STATES PATENT OFFICE Application June 18, 1937, Serial No. 149,032 In France March 22, 1937 1 Claim.

This invention relates to a stethoscope and it is one object of the invention to provide a device of this character which is so constructed that while the sounds as heart-beats will be amplified and interference by other noises will be eliminated, the heart-beats will be clearly heard.

Another object of the invention is to so construct the device that it includes a stethoscope and a microphone, an airtight connection being provided between the two instruments so that the diaphragm of the microphone only has vibrations transmitted to it from the diaphragm of the stethoscope and is not subjected to the effects of extraneous noises.

Another object of the invention is to provide a device of this character wherein the microphone and the stethoscope are connected by a rubber tube of small diameter, thus reducing to a minimum the air which must be acted upon in transmitting vibrations from the stethoscope to the microphone.

Another object of the invention is to provide a device of this character wherein the housing of the microphone is provided with a very small hole to permit restricted communication between the interior of the microphone and the outside air.

The invention is illustrated in the accompanying drawing wherein the single figure is a schematic View showing the improved device partially in section and partially in elevation.

Referring to the figure, itl will be seen that the device consists briefly of a stethoscope I and a microphone 2 connected by a rubber tube 4, which is only of suicient length to permit convenient use of the device, and of small diameter. Ends of the tube are fitted tightly about the necks 5 and l which are formed integral with and project from the centers of the microphone and the stethoscope. The stethoscope has a concave front face la. Since the stethoscope I is closed at its front by a diaphragm 3 secured about its margin to the marginal line Ib of the stethoscope and the microphone is closed at its front by a diaphragm l, a certain quantity of air will be trapped in the device and the eiects of outside atmospheric air will be eliminated. Therefore when the device is in use and the stethoscope placed over a persons heart the diaphragm 3 Will be vibrated in response to pulsations of the heart l0 and the vibrations transmitted through the tube to the microphone where they will serve to impart vibrations to the diaphragm 1 and a doctor will be able to clearly hear the heart beats without interference by other noises. A minute open- 5 ing 8 is formed in the housing of the microphone, to serve as a leak opening, and prevent splitting of the diaphragm by excessive air pressures during use of the instrument.

I therefore claim:

A stethoscope comprising a solid body having a concave front face, a marginal lip on the periphery of said face a membrane carried by said lip and covering said front face, an integral tubular neck leading rearwardly from the center of said 2l body, a microphone having a cup shaped housing open at both ends, a second integral tubular neck extending from the small end of said housing and a diaphragm bearing against and closing the large end of the housing, a exible rubber tube of rela- 30 tively small diameter extending between said solid body and said microphone and having its end portions tightly secured to said tubular necks to reduce leakage losses, and said microphone housing having a minute unobstructed perforation there- 35 in, said perforation being spaced from the integral tubular neck and constituting a safety leak opening.

SILVIO SILKA. 

